The existing retractable curtains such as Roman curtains, generally achieve retracting via cords located at least two sides of the curtain body. The upper end of the cord is tied to the winding shaft of the curtain, the winding and unwinding of the cord is controlled by a retractor, and the lower end of the cord is tied to the bottom of the curtain. Through visual inspection, the length of the cord (the length herein specifically refers to the length of the cord capable of passing through the curtain body) is adjusted by adjusting the connection position between the lower end of the cord and the curtain to cause the lengths of respective cords are the same, or otherwise different lengths will result in varying height of the curtain and cause the unbalance of the curtain. Moreover, in actual installation and use, the length of the cord may required to be adjusted according to the different weight of the curtain. Thus, a curtain capable of adjusting the length of the cord conveniently is desirable.